For Windows you can use the official Firmware Download Tool by Espressif!

Settings:

• Baud rate 115200
• Flash size 4MB (megabyte) or 32mbit (megabit) (depending on your module)
• Flash Mode DIO (or QIO, depending on your module)
• 0x0000 rboot.bin
• 0x1000 blank_config.bin
• 0x2000 main.bin (or otaboot.bin)
• 40MHz

1. Download otaboot.bin, rboot.bin and blank_config.bin.
2. Connect your device to your FTDI adapter in flash-mode (Normally hold down device button while connecting).
3. Use esptool.py to flash it in your device:

First, erase flash:

esptool.py -p /dev/<your_ESPPort> erase_flash

Normally, your ESPPort will be something like /dev/tty.USB0000

Then, set your device in flash-mode again, and flash the new firmware:

esptool.py -p /dev/<your_ESPPort> --baud 115200 write_flash -fs 4MB -fm dio -ff 40m \
0x0 rboot.bin 0x1000 blank_config.bin 0x2000 otaboot.bin

Note: If you use an old version of esptool, you must change -fs 4MB to -fs 32m.

4. You must configure wifi network and OTA repository. To configure wifi settings, device generates its own Wifi in AP mode. You must connect to it in order to setup your wifi network. Simply take your iOS device, go to Setting -> Wi-Fi, and search a SSID with LCM- followed of last MAC address, connect to it, and wait a few seconds until a web appears showing you all wifi networks that the device has found. Select yours, and enter password. Don't touch Join button yet!!

Now, you must configure OTA repository as well. It's very important that you configure it right, because you can not change it in the future (If you make a mistake, you must erase and flash device again).

Important!!! Make sure to copy this as it is shown!!! Its case-sensitive!

• OTA repository for Contact Sensor:

HomeKidd/ESP8266-HomeKit-Contact-Sensor-Elgato-Eve-Door-Window

• OTA binary file:

main.bin

5. To finish initial setup, click Join button and wait about 7 minutes until process finish (While installation is working, device doesn't show anything, and buttons don't work). After that, LED turns on for a couple of seconds and you will be able to add your accessory to your HomeKit ecosystem using Home App.

Note: If installation fails, you must start all process again from step 2.

Note2: LCM-xxxx UI will looks different because my custom version is still under development.

Please DONT use the Firmware update button when using it without OTA, it may brick the ESP and re-flashing is needed!!!! It will be fixed as soon as possible 😄

Download main.bin file from Releases, rboot.bin and blank_config.bin.

Then, continue with point 2 of Installation with OTA replacing otaboot.bin with main.bin, and ignore OTA configuration part.

Note: If pairing fails, you can unpower your device, repower it, and start HomeKit setup again (Wifi settings keep configured).